| Sierra Item # | OE/Competitor # | Quantity | Description | Image | Comments |
| 18-2552 | GLM Mallory Mercruiser Stern Drive
- 27-331791
- 27-331792
- 27-33179B2
| 1 | Thermostat Cover Gasket |  | N/A |
| 18-2553 | GLM Mallory Mercruiser Stern Drive Osco
| 1 | Thermostat Cover Gasket |  | N/A |
| 18-2554 | GLM Mallory Mercruiser Stern Drive
- 27-41812
- 27-41812B
- 27-41812Q
- 27-90556
Osco
| 1 | Thermostat Cover Gasket |  | N/A |
| 18-2917 | GLM GM Mallory Mercruiser Stern Drive
- 27-33179
- 27-53045
- 27-530451
- 27-53045B1
- F10077105
- FI1101276
- FI1101291
- FI5000096
OMC Inboard OMC Stern Drive
| 1 | Thermostat Gasket |  | N/A |
| 18-3551 | Chrysler Inboard Crusader GLM Mallory Mercruiser Stern Drive
- 32728
- 35884
- 59137
- 59137A1
- 67464
- 8052731
- 8072521
- 807252T1
- 8M0089715
Osco Pleasurecraft
| 1 | Thermostat |  | N/A |
| 18-7173 | Chrysler/Force/US Marine GLM Johnson/Evinrude Outboard Mallory Mercruiser Stern Drive Mercury Marine
- 25-27018
- 25-30224
- 25-30224Q
OMC Stern Drive
| 1 | O-Ring |  | N/A |